S B 

i > / 

H6' 



Bulletin No. 24. 

U. S. DEPARTMENT OF AGRICULTURE. 

DIVISION OF BOTANY 



THE 



GERMINATION OF SEEDS 



AS AFFKCTKD BV 



CERTAIN CHEMICAL EERTILIZERS. 



GlEBKRT H. HICKS. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICI 
I 900. 



Library of Cc 



UNITED STATES OF / 



Chap. 



■^5. 



3iri_ 



Bulletin No. 24. 

U. S. DEPARTMENT OF AGRICULTURE. 

DIVISION OF BOTANY. 



5-3^ 



XHK 



GERMINATION OF SEEDS 



AS AFFKCTKI) BV 



CERTAIX CHEMICAL FERTILIZERS. 



GILBERT Hv HICKS. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 
I 900. 



H? 



.w^^ 



.ETUlVx OF TRANSMITTAL 



U. S. Department of xlaRicuLTURE, 

Division of Botany, 
WasJiinr/Um, />. C'., JanHary 25, WOO. 

Sir: I have tlie honor to submit herewith, for publication as Bulletin 
I>lo. 24, of this Division, a manuscript entitled "The Germination of 
Seeds as Aifected by Cei"tain Chemical Fertilizers," by the late Gilbert 
H. Hicks, Assistant Botanist. Mr. Hicks left with the manuscript, 
which fortunately had been completed at the time of his death, a note 
acknowledginii' his indebtedness to Mr. John C. Dabney, formerly an 
assistant in the Division of Botany, for valuable help in conducting 
the experiments. Dr. H. W. Wiley, Chief Chemist of the Department, 
has courteously read the manuscript and suggested certain amendments 
which have been incorporated in the text. 

In the rapid extension of the use of chemical fertilizers in recent 
years, our knowledge of the precise physiological effects of this kind 
of fertilizers on different plants has not kept pace with the investiga- 
tion of their purely chemical relationship with the crops and soils on 
which they are used. The application of chemical fertilizers frequently 
takes place at the same or nearly the same time as the sowing of seed, 
and while experience has often shown the partial loss of a crop, appar- 
ently from some injurious influence of the fertilizer on the seeds, little 
definite practical knowledge has thus far resulted from these occasional 
accidents. The general conclusion that a commercial fertilizer, unless 
known to be of a noninjurious kind, should not be brought into direct 
contact with germinating seeds should be made the basis of established 
practice. 

EespectfuUy, Frederick \. Coville, 

Botanist. 

Hon. James Wilson, 

Secretary of Agriculture. 

2 lYlARSliyuJ 

D. ot 0. 



CONTEXTS. 



Pag& 

Iiitroclnction ;! 

History of previous work (J 

Department experinieuts !) 

Trials with wheat 11 

Trials with lettuce seed 12 

Trials with radish seed 13 

Trials with crimsou clover seed 14 

Couclusious 15 



ILLUSTRATIONS. 



Page. 
Plate I. — Fig. 1, Wheat experiment with potash. Right, check ; left, potash 
sowD in the rows. Fig. 2, Wheat experiment with phos- 
phoric acid. Right, sown in the rows; left, mixed with 

the soil 11 

II. — Fig. 1, Wheat experiment with lime. Right, sown in the rows; 
left, mixed with the soil. Fig. 2, Wheat experiment 
w^ith mixed fertilizers. Right, sown in the rows; left, 

mixed with the soil 11 

4 



THE GERMINATION OF SEEDS AS AFFECTED BY 
CERTAIN CHEMICAL FERTILIZEHS. 



INTRODUCTION. 

A large number of germination ex])erinients have been made to ascer- 
tain the effect of different cliemicals n])on tlie sjjronting of seeds, lu 
earlier times the object of these experiments was principally to dis- 
cover, if possible, some chemical to assist in the germination of old, 
weak, or naturally siow-germinating seeds. More recently such inves- 
tigations have been conducted mainly in connection with the use of 
fungicides and insecticides, to learn in what strengths chemicals might 
be applied to seeds without seriously injuring their vitality. As a rule 
it has been found that the germination of seeds soaked in solutions of 
bases or salts is retarded or even entirely prevented unless these are 
extremely dilute, the injury being proportionate to the concentration of 
the chemical employed. 

In some instances it has been claimed that certain chemical solutions 
quicken the germinating power of seeds, and occasionally these claims 
have been (juite startling. 

But interesting and important as have been the experiments in which 
chemicals were applied to seeds which were afterwards placed in a 
germinator to sprout, conclusions drawn from the results of such experi- 
ments are not to be relied ujjon as applied to seeds planted in soils to 
which fertilizers have previously been applied. 

Here the problems involved are much more com])lex. In the former 
case the seed is in contact for a short time only with a chemical solu- 
tion and one whose nature is known, and rarely indeed is this solution 
present after the radicle has appeared through the seed coat. Here 
the chemicals remain in the soil in more or less direct contact with the 
seed from first to last. Moreover, the chemical processes continually 
taking place in the soil have themselves a marked effect upon germina- 
tion. Add to this the hidden changes which the fertilizer constituents 
are constantly undergoing in contact with the humic acid, carbon diox- 
ide, and various salts in the soil, and we hud that a study of the rela- 
tion of fertilizers to germination involves one in problems of a very 
difficult and yet withal of an exceedingly interesting and imiwrtant 
character. 

5 



6 

Comparatively little research lias been made in this field. The pres- 
ent i)aper is intended to be merely suggestive, and is preliminary to 
more extended research in the same line which the writer hopes to 
uiidertahe. 

HISTORY or PREVIOUS WORK. 

One of the earliest imi)ortant contributions to this subject was made 
by Taut[)h(eus in 187(!. In his experiments such salts were employed 
as are found to a greater or less extent in commercial fertilizers. They 
were ai)plied to the seeds in solutions of various strength from O.o to 5 
per cent, and the seeds were then placed in a germinating apparatus. 
Wheat, rye, rape, maize, beans, and pease were tested in tins way, a 
check test being conducted with distilled water. The checks always 
germinated best, although rape seed showed scarcely any injury from 
the use of chemicals, even in solutions concentrated to a strength as 
great as 2 per cent. In the other seeds the vitality was seriously 
injured whenever the salt content of the solution was greater than 0.5 
per cent. 

The chemicals employed by Taiitplueus were potassium chloride, 
sodium chloride, calcium nitrate, sodium nitrate, potassium sulphate, 
ami hydric di-potassic phosphate. The plumule and radicle in all the 
experiments showed a normal development, l^lie seedlings, however, 
were more vigorous in the checks, except in the case of sodium chloride, 
where a o per cent solution gave stronger plantlets than where dis- 
tilled water was used. He concludes that fertilizers which contain 
plant food in an easily soluble form should not be used in large amounts, 
at least immediately before the seeds are planted, lest their concentra- 
tion in the soil become so great as, on the one hand, to destroy the 
vitality of the seed, or, on the other, to injure the development of the 
seedlings. 

About the same time (ISTG) Henri Vilmorin i)ublished a short article 
in which he states that when the u])per stratum of the soil contains a 
large proportion of mineral fertilizers, e. g.. Chili saltpeter (sodium 
nitrate), beet seed germinates very slowly or not at all. Yilmorin's 
experiments were conducted in pots containing earth, to which, after 
weighing, difl'erent fertilizers had been applied in amounts varying from 
0. -"> to .") ])er cent. The germination of wheat and beet seeds sown in 
these pots was retarded to a marked degree when potassium nitrate, 
calcium phosphate, and especially sodium nitrate were used in amounts 
equaling 5 per cent of the weight of the earth. With 10 per cent sodium 
nitrate the wheat and nine-tenths of the beet seed failed to germinate. 
It should be stated here that never in actual practice would the propor- 
tion of fertilizer to soil amount to anything like 5 per cent. Sodium 
nitrate is usually employed in quantities ranging from 150 to 300 pounds 
per acre. The soil on one acre to the depth of 8 in. weighs approxi- 
mately 2,000,000 pounds.^ If, however, the fertilizers were drilled in 

' See Wiley's Principles and Pi'actice of Agricultural Analysis, vol. 1, p. 102. 



with the seeds, the percentage of saltpeter in the soil coming into 
immediate contact with the seeds, might readily reach the danger point. 

Hindorf claims that magnesium chloride and calcium chloride used 
in proper amounts exercise a favorable ett'ect upon the germination and 
growth of wheat, rye, barley, oats, peas, red clover, and rape, and that 
they never cause injury unless used iu greater amounts than would 
occur iu agricultural practice. The injury which tlieu r(^sults he 
attributes to cliloriiic. 

Nessler (in 1877) stated that he had noticed that hemp seed sown iu 
fields fertilized with ordinary cooking salt at the rate of 1550 kilos })er 
hectare germinated unevenlj^ and nuule a poorer dev('lo[)ment than in 
other fields. Experiments led him to conclude: 

(1) A 0.5 per cent solution of cooking salt is injurious to the germi- 
nation of rape, clover, and hemp. Wheat withstands this solution, 
but is injured by a 1 per cent solution, and liemp by a quarter of 1 
per cent. 

(2) A 1 per cent solution of ammonium suli)hate had no appreciable 
eifect upon wheat grains, but the i^lants were injured somewhat by a 
0.75 per ceut solution. 

W. -larius (in 1885) studied the effect on germination of various salts 
used in comnu^rcial fertilizers, and concluded that in general (with 
some notable exceptions) solutions of these salts in strengths of d.i' and 
0.4 ])er cent favorably affected germination; also that no ill effects can 
I)ossibly result from the use of fertilizers, since their solntiou in the 
soil can never exceed 0.4 per cent. In his pa[)er the conclusions of 
Tautphoeus and Nessler are criticise<l. 

Jarius's experiments were conducted in ])()ts of jture sand ])revi()usly 
moistened for twenty-four hours with the solution. Tlu' seeds were 
planted so that one half of each, including the micropyle. projected 
above the surface, "in order," as the author says, "that observation 
might be facilitated and an unimpeded access of air be secured." This 
impractical method of making the tests largely or (|uite invalidates the 
conclusions drawn by the experimenter, at least from a practical 
stau(!p()int. 

A more important study of this subject, l)ecause conducted under 
conditions nearer to those of the field, was published in I81)(! by (Maudel 
and Orochetelle.' In order to make use of an inert substance which 
would play the mechanical role of the soil without giving any chemical 
reaction iu contact with the dissolved salts, they employed chemically 
pure (as nearly as obtainable) sterilized sand. Four hundred grams 
of this sand were placed iu a porcelain saucer and the seeds laid 
equidistantly ui)ou the surface; another layer of 400 grams of sand was 
placed on top of them, the seeds of all the species being i)lanted at a 
uniform depth of 8 to 10 millimeters. In order to maintain as nearly 
as possible the same degree of moisture iu all the saucers, the amount 



Aunalos Agrononiiqne, 1896, i)i>. lol to 112. 



of liquid supplied was based upon the amount of sand (800 grams) 
rather than upon the strength of the solution. After ascertaining the 
amount of liquid (200 cubic centimeters) necessary to moisten 800 grams 
of sand, each of the lots after planting received this amount of dis- 
tilled water, together with a solution of the chemical more or less 
dilute, according to necessity. Readily soluble materials were used, 
as potassium sulphate, ammonium sulphate, sodium nitrate, and potas- 
sium chloride. Slag and superphosphates were mixed with the super- 
ficial layer of the sand, direct contact with the seeds, however, being 
avoided. The results of these experiments are worth a somewhat 
extended mention. 

Potash fertilizers under the form of sulphate or chloride of potassinm 
in general retarded germination, this retardation being greater for the 
chloride than for the sulphate; the difference was especially noticeable 
for the Leguminosae and tlax. 

Ammonium sulphate had a disastrous effect upon the sprouting, 
though in unequal degrees, colza, flax, wheat, and mustard being very 
sensitive to its influence, while sainfoin and wheat were less so than 
any other seeds. To n)ake sure that this injury was not due to too 
large an amount of the fertilizer, the experiment was repeated with 
wheat, oats, barley, colza, clover, and beans in solutions of 0.5, 1.2, and 
5 parts per 1,000 of the sulphate of ammonia. The results showed that 
wheat, barley, and oats are practically insensible to this salt in solu- 
tions up to a strength of 2 parts per 1,000, but a 0.5 part per 1,000 
affected colza slightly and clover to a marked degree. With 5 parts 
l)er 1,000 of the salt, all germination was arrested. 

Sodium nitrate acted in a manner similar to ammonium sulphate, but 
less enegetically. The 1 part per 1,000 solution had no appreciable 
effect upon wheat, barley, sugar beet, colza, and beans, but seriously 
injured buckwheat and to a considerable extent clover. The 2 j^art 
per l,(t00 solution had but little effect upon wheat, barley, and colza, 
but entirely prevented germination in buckwheat and beans, while 
sugar beet dropped off considerably and clover was badly injared; all 
the seeds germinated more slowly in this solution than in those of less 
strength. In the 5 part per 1,000 solution no seeds sprouted except 
barley, which germinated 100 per cent. 

Phosphoric acid was used in the form of slag and superphosphate, 
the former being alkaline and the latter acid. In very feeble amounts, 
2 parts per 1,000 and less, tlie addition of superi)hospliate slightly 
hastened germination; with 1 parts per 1,000, on the contrary, a con- 
siderably less number of seeds sprouted. The authors conclude that 
in acid soil the use of superphosphate does not retard germination, if 
the free acid is quickly combined with the bases of the soil. 

The slag favored germination in all cases, especially in those of the 
Leguminosae. An attempt was made to ascertain whether tViis advan- 
tage was due to the ])hosplioric acid or to the lime, and it was found 



that the basic phosphate of lime acted favorably upon the germii)ation 
of vetches, while the acid phosphates were injurious. Free lime gave 
better results than the carbonate, but was inferior to the slag. 
Summing up, the authors conclude: 

(1) In the amounts employed, and leaving the seeds constantly in 
contact with the material used, sulphate of ammonia, sulphate of soda, 
chloride of potassium, sulphate of potassium, and the superphosphates, 
exercised an injurious action upon the germination of seeds in general. 

(2) Not all the species sown were influenced to the same extent; for 
example, the wheat resisted the best among the species tested, whereas 
lentils, lucerne, and flax were very sensitive to the action of the fertili- 
zers used. 

(3) Alkaline substances with a basis of lime or of potash favored in 
a marked degree the germination of certain seeds, notably those of the 
Leguminosae. The slag used produced better efl'ects than the lime 
alone. 

In the same paper the authors give the results of experiments con- 
ducted to obtain information concerning the acids set free or originat- 
ing during the germination of seeds, which showed that the amounts 
of acids thus formed are sometimes very great; hence it is conchided 
that lime, slag, and li(|uid manure act by saturating these acids in ])ro- 
portion to the amounts formed. Also, that the loss of jiliosplioric acid, 
which is excreted in considerable amount in the germination of wheat, 
for instance, is hindered by these alkaline substances, and tlius con- 
served for the use of the young plant. These conclusions, in the opinion 
of Claude! and Crochetelle, explain to a certain extent the beneflcial 
effect of lime, slag, and ashes ujxm acid soils. Seeds of clover were 
found to produce more acid for a given weight than any other seeds 
studied, thus explaining the fact that clover does not appear in acid 
soils prior to the addition of lime, ashes, or slag. 

Professor Buffum, of the Wyoming State Exi)eriment Station, made 
quite an extensive study of the eftect of alkali soils upon germination, 
and found that even small per cents of alkali in the soil retard germi- 
nation, although as a rule about as high a per cent of seeds germinated 
in a soil containing J i)er cent of alkali as in alkali-free soil, provided 
the seeds were left long enough. 

DEPARTMENT EXPERIMENTS. 

In any study of the effect of fertilizers upon the germination of seeds 
planted in the ground the following possibilities should be kept in mind : 
fertilizers may influence — 

(1) The swelling stage. 

(2) The nature and availability of the reserve materials. 

(3) The awakening and growth of the embryo. 

(4) The young si)rout before it reaches the surface of the soil. 

We expect to show in this paper that the principal effect is upon the 



10 

sprout after it has broken through the seed coat. It has already been 
established by Deheraiu and other investigators that plants in the 
seedling- stage absorb a proportionally greater amount of mineral mat- 
ter than in more advanced periods of development. Indeed, in the 
case of the bean, soda is taken up in the early life history of the plant, 
whereas none whatever is used when the plant is fully developed. 

In experiments conducted by us in one of the greenhouses of the 
U. S, Department of Agriculture the following kinds of seed were used: 
Jones's Winter Fife wheat, Curled Simpson lettuce, French Breakfast 
radish, and crimson clover. Previous tests had shown that all of the 
varieties were of strong vitality. Common potting soil, sifted and 
clean, was thoroughly mixed and i)laced in greenhouse "'flats." At the 
beginning of the experiment each flat was given enough water to sufitice 
while the experiment was in progress, and all were treated alike 
throughout the test except in the matter of fertilizers. A check flat 
containing soil onl)- was provided for each kind of seed. 

The fertdizers used were the following: Xitrate of soda, nuiriafe of 
potash, bone black made soluble by treatment with sulphuric acid, and 
lime made from powdered oyster shells. In addition to these, there 
wasemi)loyed a mixed or "balanced-' fertilizer consisting of bone black 
(treated as above), 000 parts (by weight): muriate of potash, 100 parts, 
and nitrate of soda, -!00 parts. This fertilizer contained approximately 
the following proportions of ])lant food: Nitrogen, 23.7 per cent; phos- 
phoric acid, .")4.7 per cent; potash. 21.5 per cent. It is to be noted that 
all of these fertilizers are readily soluble in cold water. The seeds in 
each test were plump and sound and approximately of the same size. 

The varieties were all planted at the same depth in four rows, (;ach 
containing an equal number. In no case was the soil firmed after 
planting. Fifty cubic centimeters of fertilizer were added to the soil 
in the following manner: In one flat of each experiment 12.5 cubic cen- 
timeters was e({ually distributed in each row, the seeds sown upon the 
fertilizer, and a covering of soil added. In another flat the top inch 
of soil was carefully removed and 50 cubic centimeters of the fertilizer 
thoroughly nuxed with this soil, which was then replaced and the seeds 
planted therein. A third flat contained soil only, as above stated. 

The weight of 50 cubic centimeters of each fertilizer was as follows: 
Bone black, 43.5 grams; muriate of potash, 43.0 grams; nitrate of soda, 
57.5 grams; lime, 31.0 grams; mixed fertilizer, 35.5. The fertilizers 
were used in the following strengths by weight: Bone black, 1.32 per 
cent; muriate of potash, 1.31 i)er cent; nitrate of soda, 1.75 per cent; 
lime, 0.94 per cent; mixed fertilizer, 1.08 per cent. While these pro- 
portions are greater than would obtain in ordinary practice, it is believed 
that they were not too large to give reliable results. 



ji No. 24, Div. nf Botany, Dept. nf Agr. 



Plate 





>>*v 







Fig. 1.— Wheat Experiment with Potash. Right, Check; Left, Potash sown 

IN THE Rows. 







Fig. 2.— Wheat Experiment with Phosphoric Acid. Right, sown in the Rows; 
Left, mixed with the Soil. 



Bui. No. 24, Div. of Botany, Dep-t. of Agr, 



Plate 11. 







Fig. 1.— Wheat Experiment with Lime. Right, sown in the Rows; Left, 
mixed with the soil. 




Fig. 2.— Wheat Experiment with mixed Fertilizers. Right, sown in the Rows; 
Left, mixed with the Soil. 



u 



TRIALS WITH WHEAT. 



Ill the experiments with wlieat tour rows of 50 seeds each were used 
in each test (Pis. T, II). In the tbnowing tal)h>, wiiich summarizes tlio 
results, the i)ercenta<ies given are the average of tlie four rows: 

Effect of chemlcul fcrtUlzi.vH 011 the (icrmination of Jones's If'intcr Fife wheal. 



Fertilizer. 


How fertilizer was applied. 


Time re- 
(jiiired for 
genu illa- 
tion of first 
sprouts. 


Average per 
ceut sprouted. 


Aveiai;<> 
height of 

sjiroiits 
(mm.) on 
tilth day. 






Days. 


Til 5 
(lays. 


In 10 
days. 

00 

Oil 

85. 5 

80.0 

00 

00 

!):!. 5 

90. 5 
0.0 

SO. 
oil. 5 








00 
00 
51.5 

87.0 

01) 

00 

81 

S5 

(1(1 

4(). 

80.5 




Potash (KCl) 








Phosphoric acid 
(boue black). 

Xitrogeu (Xa>>'0.(). 
Liii^e (oyster shells) 
Mixed 


|S(]\vii iu the rows 

(Mixed with soil 


:}.o 

2. 5 


Hi. li 
■Ki. 2 








ISowii ill the rows 

\Mixed with soil 


2. 5 
■ 2. 5 

5. 5 

3. 5 
2 5 


:u..-. 

48. 2 
(10. 




1 .'). l 




51. 









Analyzing these results we notice, first, that the potash and nitrogen 
fertilizers ])revented germination entirely. 

Second, that in every case at the end of four days the geriiiination 
was greater when the fertilizers were mixed with the soil than when 
they were sown in the rows and the seeds placed in direct contact, 
although the difterence in tlie case of lime was very sliglit. 

Tliird, that germination was retarded wlien thc^ fertilizers were in 
direct contact with the seeds, excei>t in the lime experiment. 

Fourth, that on tlie lifth day the germination of tlie wlieat sown in 
soils mixed with the phosphoric acid and lime fertilizers was only 
slightly less than that of the checks, and that it had nearly or tpiite 
caught u]) with the checks on the tenth day. 

Fifth, that lime in the rows gave a slightly greater percentage of 
germination than the check on the tenth day. The increa.se, however, 
is not large enough to warrant the conclusion that lime is really 
beneficial to germination. That it is, on the contrary, to a certain 
extent detrimental if used in amounts equaling 0S)\ per cent may be 
inferred from the fact that the average length of the sprouts was con- 
siderably less on the fifth day. even when the lime was mixed with the 
soil, and much less wUen sown in the row. 

The experiment teaches that care should be exercised iu aj)plying 
muriate of potash and sodium nitrate to soils in which wheat is to be 
sown, as an excess of these salts will seriously injure and may prevent 
germination. Also, that a combination of sulphate of lime with acid 
phosiihate and a little free sulphuric acid is not likely to injure the 
germination of wheat, even when used in some excess. 



]2 

The serious damage caused by the mixed fertilizer was undoubtedly 
due to the potash and nitrogen which it contained. 

After the completion of the ten days' experiment the unsprouted 
grains of wheat were taken from the nitrogen and potash flats and 
tested between damp blotters in the laboratory, with the following 
results : 

Lahoratorii test of residual irlnat. 



Fertilizer. 


How fertilizer was applied. 


Per cent 
gerrai- 
nated. 


Potash { 




.50 




70 




49 















Many of the seeds were found to be decayed when taken from the 
flats. 

TRIALS AVITH LETTUCE SEED. 

Lettuce seed, if kept thoroughly wet for the first forty-eight hours 
of a germination test, si)routs very freely, even as high as 98 or 100 
per cent by the thii*d or fourth day. In these experiments this excess- 
ive moisture was not maintained, hence the low germination of the 
check. The seed was planted in the afternoon of May 19. Four liun- 
dred seeds M^ere used in each test. 

Effect of chemical fertilizers on the germinaliou of Curled Simpson lettuce seed. 



Fertilizer. 



Potash 

Phos])horic acid . 

IsTitrogen 

Lime 

Mixed fertilizer . 



How fertilizer 



apjilied. 



Fir.st sprouts. 



Per cent 
germiuated 

on the 
fourth day. 



/ In the row.s Ko sprouts. 

\ Mixed with soil Xo sprouts. 

f In the rows Ma v 2<), \>. ni . . Xo sprouts. 

> Mixed with .soil May21,p.ni.. 2.5 

I In the rows Xo sprouts. 

\ Mixed with soil i Xo sprouts. 

( lu the rows May23,a.m.. 0.75 

\ Mixed with soil i May 22, a. ni . . 4.0 

I I In the rows | No sprouts. 

\| Mixed with soil ! , Xo sprouts. 

40.5 



Check j May 21, a m 



Per cent 
germinated 

on the 
twelfth day. 



Xo 
Xo 



Xo 
Xo 



Xo 

Xo 



sprouts. 

sprouts. 

2.5 

45.25 
sprouts, 
sprouts. 

36 

39.75 
sprouts, 
sprouts. 

73 



Potash and nitrogen j^'evented germination entirely, as in the case 
of wheat; furthermore the mixed fertilizer had the same effect. Phos- 
phoric acid and lime greatly retarded germination, and even prevented 
it to a large extent. It is noticeable, however, that although the phos- 
jiboric acid mixed with soil appeared to be slightly more favorable than 
lime under the same circumstances, yet the latter really affected germi- 
nation much less injuriously, as evidenced by the fact that when in 
direct contact witli the seeds the i)hosplioi'ic-acid fertilizer almost com- 
pletely prevented germination, giving only 2.5 per cent sprouts on the 
twelfth day, while 36 per cent sprouted in the lime test within that 
period. 



13 

At the close of the greeubouse experiment part of the sound lettuce 
seeds were removed for a test between damp blotters in the laboratory. 
The results are very interesting, since they indicate that the principal 
injury from the application of the fertilizers, especially when mixed with 
soil, accrued to the young sprouts after leaving the seeds and while 
yet beneath the soil, rather than to the seeds themselves. The labora- 
tory tests continued three and one-half days. One hundred seeds were 
used in each test. 

Laboratory test of residual lettuce seed. 



Fertilizer. 


How fertilizer was applied. 


Per cent 
germinated. 


-r^ X , ( 




62 


Potash 1 




93 


, 




80 


Pbospliorio acid ■ 




Xot tested 




36 


Nitrogen 


Mixed with soil 


79 

Not tested. 

Not tested. 

90 

93 




Mixed with soil 




Mixed lertilizer 









The sprouts were mostly normal and healthy in the potash and 
mixed fertilizer tests. Those derived from seeds which had been in 
direct contact with the nitrogen and phosphoric acid were somewhat 
sickly and weak, rnfortunately, the record is not entirely complete, 
since neither the seed tested in phosphoric acid in rows nor the limed 
seed was given a laboratory test; but the very liigh germination of 
the two mixed-fertilizer lots, neither of which had si)routed at all while 
in the soil, adds further evidence to the apparently established fact 
that the injurious effects of the fertilizers were i)rin('ipally wrouglit 
upon the hypogeous seedlings, and that owing to the protecting power 
of their teguments, perhaps to some extent also to the dormant condi- 
tion of the seed contents, the seeds themselves were not injured by the 
fertilizers employed. 



TRIALS WITH RADISH SEED. 



The soil experiment represented in the table below occupied ten 
days. Two hundred seeds were used in each trial. These were planted 
in the afternoon of May 21. 

Effect of chemicul fertilizers on French Breakfast radish seed. 



Fertilizer. 



How fertilizer was aiijilied. 



First sprouts 
appeared. 



Per cent 
of germi- 
nation. 



p„f.,j^]i /In the rows 

i\Mi.\ed with soil . 



Phosphoric aci.l ! ' ^". ^^"', ''".^yf 



soil . 



Nitrogen 

Lime 

Mixed fertilizer 
Check . .- 



}Nc 
Mi 

M; 

M, 
M; 
M: 



/In tlie row 
(Mixed with soil 

fin the rows 

\Mixed with soil 

/In the rows j M 

iMixed with soil ' M 

I M 



IV 26, 

>y ^+. 

:iV 25, 
IV 26, 
I'v 24, 
.!do - 

t.y -'. 

IV 24, 

ly 24, 



a. m 
a. ni 
p. ni 
a. m 
a. m 



1.5 

19.0 
O.'i.o 
2. 
6.5 
37.5 
93.0 
34.5 
92. 
96.5 



14 

Plere agaiu it is seen that the i)otasli and nitrogen fertilizeis practi- 
cally i)revented germination. The fact is striking, however, that, while 
the sprouting was seriously injured in all of the tests in wliich the seeds 
were sown directly upon the fertilizers, when the latter were mixed 
with the soil the germinatiou of the radish seed was nearly as high as 
in the check test. 

An examination of the radish seeds remaining at the close of the soil 
experiments revealed the fact that many of them which had beeh in 
immediate contact with the potash and nitrogen were badly decayed, 
while those taken from the soil mixed fertilizer lots were generally, to 
all apjiearance, quite sound. This I attribute mainly to the fact that 
in the case of wheat and lettuce " seed " we are really dealing with 
fruits, in which the proper seed is encased in external teguments, whereas 
the radish seed has only the true seed coats. 

Laboratory tests were made of radish seed taken from the flats of the 
potash and nitrogen experiments, with the following results: 

I.ithoralorij testa of rvsidiuil radisJt seed. 



Pertilizer. 



How fertilizer was applied. 



Pof.,^., /In the rows 

■^"^■'"'^ IMixed with soil 

xr-i ,„ , , (In the rows 

^'t'°«^" \Mixe.l with soil. 



Per cent 
germi- 
nated. 



These figures are in decided contiast Avith those given in the table of 
germinations of radish seed in soil treated with the potash and nitrogen 
fertilizers, and show that while radish seed is much more susceptible 
to the action of fertilizers than the others tested, when in direct con- 
tact, nevertheless the effect is mainly produced upon the seedlings. 

TRIALS WITH CRIMSON CLOTER SEED. 

A soil test was made with crimson clover seed which lasted eleven 
and one-half days. Two liundred seeds were used in each trial. These 
were planted May 20, p. m. 

Effect of cliemical fertU'cers ox crimson clover seed. 



Pertilizer. 



Potash. 



How fertilizer was applied. 



/In the rows 

\Mixed 

-ni 1 • -1 /In the rows 
Phosphoric acid iMixed 

/In the rows 
IMixed 

/In the rows 
IMixed 

Mixed fertilizer iP.^^'iV""'^ 



Nitrogen 
Lime 



Check 



\Mixed. 



First sprouts ^^^ " ,^ 
innenred "^ germi- 

appeared. nation. 



No sprouts 

do 

do 

May 23, a. m.. 

No sprouts 

do 

^lay 28, a. m.. 

May 23, a.m.. 

No sprouts 

May 24, a. m.. 

May 23, a.m.. 



21.5 
31 



15 

Tbe injurious action of tlie fertilizers upon the crimson clover seed 
seems to have been niucli inoi'e marked tliau in the case of any other 
seed tested, l)ut any definite conclusions are ])reclnded by the extremely 
low germination of the cheek. This seed tested in the laboratory 
between moist blottei's showed a vitality of \)1 \ ])er cent. The seed, 
however, was - years old, as was the case with the wlieat also, while 
the lettuce and radish seed aie sujjposcd to liave been grown in 18'.>7. 

As with wheat, lettuce, and radish (practically i, the muriate of potash 
and sodium nitrate prevented germination. Lime, too, was almost 
l)rohibitive when sown in the rows, although it gave better results than 
any other fertilizer wheu mixed with soil. Liebenbcrg claims that the 
use of lime renders the reserve materials of the seed more available to 
the developing seedling and therefore helpful to germination. This is 
certainly not the case when an excessive amount is applied. 

CONCLUSIONS. 

Summing up the results obtained from these exi)eriments, we may 
safely conclude: 

(1) That muriate of potash and sodium nitrate used as fertilizers in 
strengths of 1 per cent or more are very detrimental to the germina- 
tion of seeds, whether applied directly or mixed with the soil, 

(2) That fertilizers composed of phosphoric acid or lime are much 
less injurious to germination than sodium nitrate or muriate of potash, 
and if not used in excess may be harmless. 

(3) That commercial fertilizers should not l)e brought into direct 
contact with germiiuiting seeds. 

(4) The effect of treating seeds with chemicals before planting is no 
index to the action of those chemicals when applied as manures to the 
soil. 

(5) That the chief injury to germination from chemical fertilizers is 
iutiicted upon the young sprouts after they leave the seed coat and 
before they emerge from the soil, while the seeds themselves are injured 
only slightly or not at all. 

(0) It is highly improbable that potash, phosphoric acid, nitrogen, or 
lime used as fertilizers actually favor germination. 



O 



hMr 



